The present invention relates to a slide bearing having a bearing bore for receiving a shaft which is at least temporarily affected by radial force. Preferred embodiments of the present invention relate to such a slide bearing in use in a gear pump with the shaft supporting a gear pump gear wheel.
Slide bearings are used, for example, for receiving drive shafts or the like in order to fix these locally. In this case, the bearing absorbs the forces acting upon the shaft, particularly those which radially affect the shaft.
It is known that slide bearings have a play adapted to the operating conditions. This is necessary so that a suitable lubricating medium which corresponds to the selected play can penetrate into the slide bearing. In the case of lubricating media which, in addition to the pure flow properties, have an increased elastic fraction, the entering of the lubricating medium into the bearing gap may be difficult; that is, sufficient lubricating medium can arrive in the bearing gap only if additional pressure is applied. Particularly in the case of slide bearings for gear pumps, in which the pumping medium is often simultaneously used as the lubricating medium, the entering of the lubricating medium into the bearing gap is very difficult; particularly because the pumping medium usually consists of liquids of a relatively high viscosity. Although, when highly viscous lubricating media are used, the play of the shaft in the slide bearing is selected to be corresponding larger, the stressing of one bearing end is often excessively high so that, in the case of higher shaft loads--despite a sufficient carrying capacity of the slide bearing--a lack of space may occur because of an inclination of the shaft in the bearing which may result in increased friction losses and, in an extreme case, even to a wedging of the shaft.
The present invention is therefore based on the task of providing a slide bearing in the case of which the danger of a wedging of the shaft is reduced and/or in the case of which a sufficient lubrication is ensured.
This object is achieved by providing an arrangement wherein at least one bearing end of the slide bearing has at least one chamfer for preventing a contact between the shaft and the slide bearing and/or for facilitating the supplying of the slide bearing with lubricating medium.
The invention has the following advantages: In that at least one bearing end of a slide bearing is chamfered toward the bearing bore, the contact danger caused by a bending of the shaft is reduced and it is achieved that sufficient lubricant is supplied to the slide bearing. Particularly if the stressing of the slide bearing takes place by a radial stressing of the shaft disposed in the slide bearing essentially in one direction, one or preferably two chamfers in the bearing ends are found to be especially advantageous. In this case, preferably the chamfer on the unstressed side has a larger construction than that on the stressed side. As a result, the body edge is shortened on the unstressed side in its longitudinal sectional view so that the shaft-caused contact danger is reduced on the unstressed side and the supply of lubricant to the slide bearing is facilitated without a significant reduction of the bearing length essentially supporting the bearing load on the stressed side. This significantly reduces the danger of increased friction losses in the slide bearing as well as the danger of a wedging of the shaft in the slide bearing.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.